• 한국지반공학회논문집
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• 제19권2호
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• pp.199-206
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• 2003

흙을 나타내는 가장 기본적인 물리적 성질중의 하나가 흙을 구성하는 입자들의 입도분포이며, 입도분포특성을 분석하기 위해 최근에 대두되고 있는 방법중의 하나가 프랙탈 이론이다. 본 연구에서는 fragmentation 프랙탈을 이용하여 흙의 입도분포곡선의 특성을 파악하였다. Fragmentation 프랙탈을 표현하는 방법에는 ‘개수-입경’프랙탈과 '중량-입경' 프랙탈이 있으며, 본 연구 결과, '중량-입경' 방법이 더 실용적이었다. 균등계수($C_{u}$)가 4이하에서는 균등계수가 증가함에 따라 프랙탈차원($D_{tot}$)이 급격히 증가하였으나, 균등계수가 6이상에서는 일정한 값에 수렴되는 결과를 나타냈다. 곡률계수($C_{c}$)가 3이상에서는 프랙탈차원은 크기가 작은 입자들의 영향을 받고, 곡률계수가 3이하에서는 큰 입자들의 영향을 받는 것으로 나타났다. 유효입경($D_{10}$)의 크기에 따른 프랙탈차원의 변화를 분석한 결과, 균등계수와 곡률계수가 같을 경우 프랙탈차원은 유효입경의 크기에 영향을 거의 받지 않는 것으로 나타났다. 전체 입자의 크기분포를 고려할 수 있는 프랙탈 개념을 입도분석에 적용하는 것이 바람직할 것으로 판단되며, 향후 프랙탈차원과 흙의 공학적 특성과의 관계정립에 대한 지속적인 연구가 필요하다.

• 한국응용과학기술학회지
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• 제23권1호
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• pp.1-11
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• 2006

The W/O emulsion was formed by mixing hydrophobic nonion surfactants of span 80 and tween 60 with kerosine, and by adding sodium silicate aqueous solution. Precipitating the W/O emulsion by sodium bicarbonate resulted in spherical silica particles. Shape and size distribution of silica particles were observed. The particles were spherical and they have narrow size distribution. Particle sizes were 9.29, 7.39 and $5.73\;{\mu}m$ at homogenizer speed of 2500, 3000, and 3500 rpm, respectively. The particle size was decreased by increasing agitation speed due to the formation of emulsion droplet. At fixed agitation speed, absorbed paraffin oil weight were measured and the $SiO_2/Na_2O$ mole ratio effects on particle size were investigated. Particle size was decreased by increasing the mole ratio of $SiO_2/Na_2O$.

• 한국축산식품학회지
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• 제42권3호
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• pp.486-503
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• 2022

This study explored the physiochemical and rheological properties of chicken breast sausages containing red ginseng marc (RGM) which contains useful components but is discarded. When compared to the control group, the use of RGM significantly increased the water holding capacity (WHC) as the particle size increased. As for the change in color value, addition of RGM resulted in an increase in a and b values; as the quantity was increased and particle size decreased, the a and b values increased significantly. The smaller the particle size of RGM, the greater was the radical scavenging activity. According to the results of the measurement of the viscoelasticity of chicken breast sausage containing RGM, the G' and G'' values increased with increasing amounts of RGM and particle size. Neither the addition of RGM nor its amount or particle size had any significant effect on gel formation temperature. The texture profile analysis (TPA) experiment examined the average TPA measurements of each sample under different measurement conditions, and no significant difference between the RGM and control groups were observed. In conclusion, when RGM is used in chicken breast sausages, the WHC, antioxidant capacity, and viscoelastic properties are affected. RGM can possibly be utilized in high value-added processed meat products if its quantity and particle size are altered based on product characteristics.

• 한국재료학회지
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• 제15권11호
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• pp.717-721
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• 2005

Silica powders were synthesized using emulsion solution containing water, nonionic surfactant of Triton N-57, and cyclohexane. Silica powders were prepared at low cost using inexpensive starting material of sodium silicate and ammonium sulfate. Morphology, size and size distribution were observed and determined using SEM. The powder was identified as silica by FT-IR and XRD analysis. Particle size and size distributions were affected by concentration of reactants, reaction time, and concentration of surfactant. Particle size were increased with increasing concentration of reactants and particles became dense with increasing reaction time. As R value increased, tile particle size was increased, reached a certain value and then decreased again. The silica powders synthesized under optimum condition were spherical in shape, $0.8{\mu}m$ in average particle size, narrow in particles size distribution, and well dispersed.

• Transactions on Electrical and Electronic Materials
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• 제14권1호
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• pp.39-42
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• 2013

The effects of particle size on the mechanical and electrical properties of epoxy/spherical silica composites were studied. The silica particle sizes were varied from 5 to 30 ${\mu}m$ and the filler content was fixed to 60 wt%. Tensile and flexural tests were carried out and the interfacial morphology was observed by scanning electron microscopy (SEM). The electrical insulation breakdown strength was estimated using sphere-sphere electrodes with different insulation thicknesses of 1, 2 and 3 mm. The tensile strength and flexural strength increased with decreasing particle size, while electrical insulation breakdown strength increased with increasing particle size.

• 약학회지
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• 제12권3_4호
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• pp.41-49
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• 1968

The optimum reaction conditions for the preparation of the precipitated calcium carbonate of an average particle size of 0.05.mu. in diameter was set in which the Box-Wilson Plan was applied. The reaction conditions are as follows; 1) concentration of milk of lime; 6.56% w/w 2) temperature; 14.24.deg. C #) velocity of carbon dioxide introducing; 1.95l/min. The crystal form was found that of calcite in X-ray diffraction analysis. The particle size was determined by the sedimentation volume measurement. The shape was identified by the elctron micro-diffraction pattern and the electron microscopic photographs.

• 한국습지학회지
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• 제13권3호
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• pp.523-534
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• 2011

충남 서해 연안역에 위치하고 있는 해수욕장, 항구, 박물관의 주차시설과 교량에서 발생되는 퇴적물의 입도분포 특성 및 오염물질 함량을 조사한 결과 다음과 같은 결론을 얻었다. 퇴적물의 입경별 % 누적중량분포를 분석한 결과 대부분 $106{\sim}500{\mu}m$사이의 입경범위가 많이 분포되는 것으로 나타났다. 퇴적물의 입경분석 결과 모든 지점에서 유효경 $D_{10}$의 범위는 $40{\sim}160{\mu}m$, $D_{50}$의 범위는 $200{\sim}810{\mu}m$, $D_{60}$는 $235{\sim}1005{\mu}m$로 나타났다. $D_{10}$의 경우 입경범위가 큰 차이가 없는 반면에 $D_{50}$, $D_{60}$은 큰 차이를 보였다. 대체로 입자크기가 작으면 작을수록 오염물질 함량은 증가하는 것으로 분석되었는데 이는 입자의 크기가 작으면 작을수록 비표면적이 증가하여 오염물질 흡착량이나 결합량이 증가하였거나 입자자체가 타이어나 배가스 분진입자일 가능성이 크기 때문으로 사료된다. 입경 크기가 ${\leq}63{\mu}m$입자에서 VS, $COD_{cr}$, TN, TP의 오염물질이 최저 2배에서 최고 14배 높은 것으로 분석되었다. Cu와 Pb은 모든 지점에서 검출되었으며 일반 오염물질과 마찬가지로 입경이 작을수록 함유량도 증가하는 것으로 나타났다. Cu 함량은 지점 별로 큰 차이가 없었으나 Pb의 경우는 신진도 진입도로인 신진대교 지점에서 다른 곳에 비해 2배에서 3배 정도 높게 검출되었다. Cd은 해수욕장이나 서천해양 박물관 지점에서는 미세 입자에서만 검출되었으나 대천항 주차장과 신진도에서는 모든 크기의 퇴적물에서 검출되었다.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.15-23
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• 1999

In recent years, environmental damage to urban area becomes serious problem due to the exhaust emissions by increasing the number of vehicle . Especially, diesel particulate matters(DPM) are hazardous air pollutant s to human health and environment. The reduction technologies of exhaust emissions from diesel engines are improvement of engine combustion, fuel quality and development of diesel exhaust aftertreatment. In this study, a diesel oxidation catalyst(DOC) that is one of diesel exhaust aftertreatments was made for performance evaluation . It was tested for NA and turbocharged engine by D-13 mode that currently be used for regulation driving test mode in Korea Scanning mobility particle sizer (SMPS) was used for the analysis of the particle size distribution with and w/o DOC. As the results , for NA and tubochartged engine, CO, THC, DPM was respectively reduced 85.7, 40.7,3.3% and 79.1, 53.1, 11.6% by DOC. Test results of particle size distribution was showed that particle number is 107 ~108per ㎤ , 2 $\times$105 ~5$\times$105$\mu\textrm{g}$/㎥ for weight concentration and 100~200nm for particle mean size in diesel engine and there is no effect to reduce the particle concentration by the DOC.

• 보존과학회지
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• 제28권2호
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• pp.165-173
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• 2012

본 연구에서는 고대 먹의 과학적이고 체계적인 분석을 통해 선조들의 조묵방법 및 기술을 파악하는 것이 연구의 목적이다. 고목재와 고문서의 묵서부의 먹을 분석한 결과 다음과 같은 결론을 얻었다. 고목재(창덕궁 신선원전 적심)를 연륜연대분석한 결과 1899년에 벌채된 것으로 나타났으며, 따라서 고목재에 씌어진 먹의 연대를 추정할 수가 있었다. 고대 먹 원료인 그을음의 단일입자크기는 고목재의 경우 평균 107nm로 가장 크게 분석되었고, 12개의 고문서의 경우 38~86nm범위를 나타냈다. 응집체입자크기 분석 결과 고목재의 경우 평균 370nm로 단일입자크기와 같이 가장 크게 분석되었으며, 고문서의 경우 평균 206~318nm로 분석되었고, 단일입자크기와 응집체입자크기 간에는 같은 경향의 분포를 나타내었다. 단일입자크기와 응집체입자크기로 그을음의 원료를 분석할 수가 있을 것으로 생각되었다. 고목재와 고문서 묵서부분의 박편상먹의 적외선 및 라만 분광분석에서는 목재나 종이의 간섭으로 먹 입자의 스펙트럼을 얻을 수 없었다. 고목재에서 분리한 분말먹의 라만 분광분석에서는 현대 송연 그을음과 유사한 라만 스펙트럼패턴을 보여, 송연먹으로 추정할 수 있었다.

• 한국입자에어로졸학회지
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• 제18권3호
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• pp.69-77
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• 2022

In order to understand the characteristics of fine particles emitted from coal-fired power plant stacks, it is important to analyze the size distribution and components of particles. In this study, particle size distributions were measured using the ejector-porous tube dilution device and an ELPI system at a stack in a coal-fired power plant. Main elemental components of particles in each size interval were also identified through TEM-EDS analysis for the particles collected in each ELPI stage. Particle size distributions based on number and mass were analyzed with component distributions from 0.006 to 10 ㎛. The highest number concentration was about 0.01 ㎛. The main component of the particles consisted of sulfur, which indicated that sulfate aerosols were generated by gas-to-particle conversion of SO2. In a mass size distribution, a mono-modal distribution with a mode diameter of about 2 ㎛ was shown. For the components of PM1.0 (particles less than 1 ㎛), the abundance order was F > Mg > S > Ca, and however, for the components of PM10 (particles less than 10 ㎛), it was in the order of Fe > S > Ca > Mg. The elemental components by particle size were confirmed.